Add web3 deprecation warning (#7334)

* Add web3 deprecation warning

* Update web3 deprecation article URL

app/scripts/inpage.js

@@ -174,27 +174,6 @@ log.debug('MetaMask - injected web3')
 
 setupDappAutoReload(web3, inpageProvider.publicConfigStore)
 
-// export global web3, with usage-detection and deprecation warning
-
-/* TODO: Uncomment this area once auto-reload.js has been deprecated:
-let hasBeenWarned = false
-global.web3 = new Proxy(web3, {
-  get: (_web3, key) => {
-    // show warning once on web3 access
-    if (!hasBeenWarned && key !== 'currentProvider') {
-      console.warn('MetaMask: web3 will be deprecated in the near future in favor of the ethereumProvider \nhttps://github.com/MetaMask/faq/blob/master/detecting_metamask.md#web3-deprecation')
-      hasBeenWarned = true
-    }
-    // return value normally
-    return _web3[key]
-  },
-  set: (_web3, key, value) => {
-    // set value normally
-    _web3[key] = value
-  },
-})
-*/
-
 // set web3 defaultAccount
 inpageProvider.publicConfigStore.subscribe(function (state) {
   web3.eth.defaultAccount = state.selectedAddress

app/scripts/lib/auto-reload.js

@@ -5,11 +5,17 @@ function setupDappAutoReload (web3, observable) {
   let reloadInProgress = false
   let lastTimeUsed
   let lastSeenNetwork
+  let hasBeenWarned = false
 
   global.web3 = new Proxy(web3, {
     get: (_web3, key) => {
       // get the time of use
       lastTimeUsed = Date.now()
+      // show warning once on web3 access
+      if (!hasBeenWarned && key !== 'currentProvider') {
+        console.warn('MetaMask: web3 will be deprecated in the near future in favor of the ethereumProvider\nhttps://medium.com/metamask/4a899ad6e59e')
+        hasBeenWarned = true
+      }
       // return value normally
       return _web3[key]
     },